The inventions described below relate the field of hand-held suction pumps intended for use in evacuating containers.
The invention refers to a hand-held suction pump for creating a vacuum in a container provided with a suction valve, comprising an elongated outer casing in which an electric motor and a piston pump driven by the motor are accommodated, wherein the pump chamber of the piston pump is connected by an inlet valve and a suction duct to a hollow tip at the free end of the casing for direct coupling with the suction valve of the container, the pump chamber being further connected by an outlet valve to an exhaust duct having a duct opening on the outer surface of the wall of the outer casing for porting an exhaust flow to the exterior of the outer casing.
A hand-held suction pump of the aforementioned kind is disclosed in EP 0 510 360 A. It is useful especially in the household field for creating a high vacuum in household containers containing food, either solid, semi-solid or liquid to be preserved in the absence of air or air access, particularly in the absence of oxygen.
The known hand-held suction device has been proven to satisfy the aforementioned need but may be subject to further improvement regarding some noise generated by the intermittent air flow which must necessarily exit the device during operation.
According to the invention, a hand-held suction pump of the present type is provided and constructed primarily so as to effect a reduction of the noise generated in exhausting the air as it is sucked out during evacuation of the container.
This aim is attained by the invention in that the duct opening of the exhaust duct on the outer surface of the wall of the outer casing of the hand-held suction pump is overlapped by a baffle which is separated by a gapped distance from the outer surface of the wall of the outer casing so as to deflect the exhaust flow exiting the duct opening by a substantial angle before the exhaust flow is discharged to the surrounding air.
By deflecting the exhaust flow exiting the duct opening of the exhaust duct by a substantial angle, it is possible to reach a substantial reduction of the noise generated by the air streams which intermittently exit the device during operation. The magnitude of the deflecting angle mainly depends on the shape and direction of the exhaust duct with respect to the contour of the outer surface of the casing at the opening site of the duct as well as on the construction and shape of the opening of the duct. In most cases, the deflecting angle is 60xc2x0 to 120xc2x0. If the exhaust duct extends mainly in a radial direction with respect to the axis of the outer casing of the suction pump and if the outer surface of the casing at the opening site extends in parallel with said axis, the amount of the deflecting angle will be substantially 90xc2x0.
Further, the deflecting direction may be varied to a great extent according to the construction of the contours of the exhaust duct and the outer surface of the casing. Thus, it is possible to deflect the exhaust flow at the baffle into the axial direction of the outer casing of the suction pump toward the top portion of the casing. In other cases, the deflection direction may be lateral. Further, it is possible to construct outlet gaps or openings at both lateral or axial sides of the baffle to simultaneously split apart the exhaust flow exiting the duct opening of the exhaust duct. At present, it is preferred that an exit port is formed between the baffle and the wall of the outer casing designed for directing the exhaust flow in a direction substantially parallel to the contour of the outer casing surface toward the hollow tip at the free end of the casing. In this way, the existing exhaust flow will be directed away from the user holding the suction pump in one hand during operation of the device.
Moreover, the construction of the baffle and of its connection to the outer casing may be freely chosen as desired according to the casing construction. At present, it is preferred to form the baffle by a wall portion of a sleeve attached to the outer casing. Such a construction of the baffle is particularly of advantage if the suction pump comprises an interchangeable terminal cap supporting the hollow tip at the free end of the casing, the terminal cap being attached by a removable sleeve which also serve to form the baffle of the invention.